The equipment used to play the game of golf has always played a significant role within the game of golf itself. Various equipment ranging from golf clubs, golf balls, golf shoes, to even golf gloves have all been used by golfers who play the game of golf. Because golf equipment is so closely related to technological advancements, the development of technology within the golf industry has changed the way the game has matured throughout the years.
Of all the various types of golf equipment that have evolved throughout the years, the development of golf clubs has made the most dramatic strides, making the game of golf more enjoyable for the average golfer. For example driver type golf club heads originally started with persimmon woods clubs woods have completely morphed into gigantic hollow titanium clubs with volumes greater than 400 cubic centimeters (cc). Iron type golf club heads have also evolved from solid iron type golf club heads to ones that now have a hollow cavity in the back of the allowing the golfer to hit the golf ball straighter and more consistently. Even putter type golf club heads have developed to have more heel toe weighting with interchangeable weights at the toe and heel to provide for more adjustable forgiveness on off center putts.
Even on a more macro level of individual golf clubs, different technological advancements have helped to improve the performance of golf club components such as the golf club head, golf club grip, and the golf club shaft. For example, U.S. Pat. No. 5,904,627 to Miyaji et al. ('627 patent) discusses a golf club shaft that comprises of three interconnected tubular members whose diameters, flexional rigidities, lengths, materials, etc. are selected to make the golf club shaft more flexible near the club head or the club grip or at the middle portion to improve performance. U.S. Pat. No. 7,338,386 to Nakajima ('386 patent) discloses another improvement to the performance of the shaft of a golf club by discussing a light-weighted golf club shaft, which can stabilize the swing orbit of a golf club head during a swing and can allow a player to swing a golf club easily and to have a consistent shot pattern by having a length of 42 to 48 inches, a weight of 35 to 50 grams, a center of gravity located within 46% to 49% of its entire length from its tip and a torque to the tip-end of the shaft ranges between 3.0 and 4.5.
Despite the above technological advancements within golf club shafts, golf club shafts have generally been designed in a vacuum, only paying attention to the design spaces available within an individual golf club, without considering performance benefits that can be achieved by looking at new design spaces available across different clubs with different shafts. Although maximizing the performance of an individual shaft within an individual golf club may help with the performance of that specific golf club, the game of golf requires the use of many different golf clubs, each club with its own shaft requiring individualized analysis. U.S. Pat. No. 6,117,021 to Crow et al. addresses this issue by disclosing a set of golf clubs comprising a plurality of shafts that decreases in length along the set. Each shaft includes a reverse taper section disposed a distance from the tip section on each shaft and the distance of the reverse taper section varies along a number of shafts as the shaft length decreases.
However, in view of all the technological advancements in the field of golf club shafts, one of the most uncontrollable variables to the performance of a golf club shaft is the actual golf swing itself. If every golfer had the same swing parameters, designing a golf club shaft to optimize the performance of a golf shot would be significantly easier. Consequently, because of the dramatic variations among golfer's swings, the optimal performing shaft for an individual golfer may need to be individually determined based on the golfer and his or her golf swing. U.S. Pat. No. 6,719,648 to Smith ('648 patent) explores this concept by disclosing a method and a system for precisely fitting a golfer to a selected stiffness of a golf shaft and to a selected flex choice of a golf shaft. More specifically, the '648 patent discloses a method and means for precisely fitting a golfer to a particular golf shaft whose values of stiffness and flex choice are applicable to a player of a specific skill level in the game of golf.
Ultimately, even if a golfer finds the correct shaft flex and stiffness for every one of his golf clubs, he would have to search through different shaft models from different manufacturers, with different weights, different flex determinants, different torque values, different tip frequencies, different butt frequencies, and different feel to ensure he or she optimizes the performance potential of his or her golf swing for different golf clubs within his arsenal. More often than not, different shafts capable of achieving one of the performance criteria desirable for a specific golfer will not be able to provide a correct match with other performance criteria; causing the golfer to make a sacrifice.
Hence, it can be seen from above that there is a need in the field for a plurality of shafts created within a matrix from which a golfer can select to maximize the performance characteristics of his or her golf swing without having to sacrifice other criteria that he or she may desire to keep consistent. More specifically, there is a need in the field for a plurality of two or more golf club shafts wherein the golfer may select to adjust only the performance criteria that he or she desires to change, while keeping other performance criteria consistent regardless of which selection he chooses.